T460-emacs-tree: sync $EXPECTED with test name

This syncs the $EXPECTED directory name with the tests filename.

Signed-off-by: Florian Klink <flokli@flokli.de>

test/T460-emacs-tree.sh

@@ -3,7 +3,7 @@
 test_description="emacs tree view interface"
 . $(dirname "$0")/test-lib.sh || exit 1
 
-EXPECTED=$NOTMUCH_SRCDIR/test/tree.expected-output
+EXPECTED=$NOTMUCH_SRCDIR/test/emacs-tree.expected-output
 
 add_email_corpus